Radial grating



L. N. LUMB RADIAL GRATING Dec. 5, 1933.

Filed D66. 27. 1930 U EL D 5' INVENTOR Z 00/: /V Lam b.

ATTORNEY Patented Dec. 5, 1933 PATENT OFFlC RADIAL GRATI'NG Louis N. Lumb, Astoria, N. Y., assignor to Irving Iron Works Company, a corporation of New York Application December 27, 1930 Serial No. 505,087

4 Claims.

'This'invention relates generally to the manufacture of ventilating flooring or grating now commonly used in industrial plants, engine rooms and similar structures, and, more specifically, is designed to produce an inexpensive but strong and artistic grating unit for use around pillars, stacks or circular floor openings. The invention finds its most useful application in the manufac ture of that type of gratings consisting of a plurality ofstraight bars which bear the greater portion of any superposed load and are spaced apart and connected oneto another by intervening bent or crimped strips riveted, welded or V otherwise fastened thereto at all points of con- I5 tact, such as is shown, for instance, in U. S. Patent No. 1,588,048 to P. L. Price, dated June 8, 1926. Heretofore, in making gratings of this type to be used around a circular opening or object, it ,I has been customary to make up the usual rectangular panels of such grating and then to out these in various ways to produce the curved, or inclined interior or exterior outlines required to fit them together in any given ring-shaped forms. This cutting and fitting has involved expenditures for labor several times larger than the manufacturing cost of the original grating units, and the resulting structure has been most unsightly.

By the present invention sections or units of radial grating can be manufactured at about the same cost as that of standard, rectangular units of thesame weight and area, and these radial units will fit together in the predetermined circle without further treatment, and produce an artise tic appearance.

of giving the bent strips, which are to be interleaved between the straight bars, crimps of standard length but of depths progressively increasing from one end to the other of each strip, and then,

0 in assembling the grating panel, or unit, placing the low crimped ends of all the strips at the end of the panel which is to abut against the column,

or form a portion of the edge of the circular opening, around which column or opening the grating floor is to be built.

Also the operation may be cheapened and simplified by dividing the crimps of each strip into groups and giving a uniform depth to each of one group, a slightly greater'depth to each one of the slightly distorting one or more of the crimps of each group so as to produce the desired regular progression or gradation in depth from one end to the other of each strip,-thereupon riveting or otherwise fastening the parts together While in In substance the invention is based on the idea next group and so on, and then, in assembling,

(o1. 94 s0 i this shape, and so rendering permanent the distortion which has thus so contributed to the desired result.

If the grating is of a type such that the bent strips have a reversed curvature between every two points of their attachment to a straight bar, such for instance as is here shown and also illustrated on a larger scale in Design Patent No. 70,382 to Paul L. Price, dated June 15, 1926, there will be a short endwise elasticity in the sides'of each crimp, and the act of riveting the tops of any one set of crimps to the nextstraight bar and strip will itself produce this desired distortion, and maintain it permanently.

The best form of apparatus at present known to me embodyingmy invention and one method of producing it are illustrated in the accompanying sheet of drawings in which i Fig-lie a plan view of a section of flooring in which my inventionhas been employed, parts being broken away.

Fig. 2 is a side view with parts broken away showing how the straight bars and bent strips may be shaped and assembled in certain preliminary steps of my preferred process of making this grating on a riveting bench.

Fig. 3 is a similar view showing another step in such process.

Fig. 4 is aperspective detail on a larger scale, and

Fig. 5 is an end view of a series of the riveting dogs employed. 7

Throughout the drawing like reference characters indicate like parts. 1, represents a panel of my radial grating having the exterior outlines 99 of a truncated sector of a circle, the center of which circle coincides with the center of the circle 4 which represents thecylindrical column or circular floor opening which is to be surrounded by a series of such panels. 2 and 3 indicate in dotted lines the locations and'exterior outline of adjacent panels of the same shape. 5, 5, are the equally spacedapart, and mutually inclined straight bars of the grating, each one being normal tothe circumference of circle 4. The bent 1 strips 6, 6, alternatewith-said straight bars and are fastened thereto at all points of contact by rivets 7, 7 V

Thestraight bars 5, 5, may all be cut to substantially the same length if a circular platform is to be built aroundjthe circular space 4, -as indicated in Fig. l, and, if the fastenings were to be rivets, said bars would have rivet holes'punched in them at uniform distances apart, but the bars would be divided into two sets, and the punching done so that the holes in one set (represented by bar 5a in Fig. 2) would be staggered with reference to those in the other set (represented by 5b in said Fig. 2), thus permitting rivets to be inserted at all points of contact between bars and strips in the usual way. The bent strips 6 would then also made of the same length, and the outer ends of all bars and strips would consequently be substantially in a larger circle concentric with that (4) in which the converging ends of the bars and strips have been assembled.

If, however, it were desired to have the completed structure fit into a rectangular space in a continuous floor of grating, or of other material, said bars and strips cou d be cut of different lengths so that when properly assembled the exterior outline of the structure so formed would be rectangular. In the same way exterior outlines of other polygonal shapes could be produced. This result can be attained also by trimming the exterior outline.

The criinps in each bent strip would be formed with the same uniform distance between rivet holes as in the case of the straight bars, so that when "strips and are assembled they can be riveted together to form a grating having a uniform mesh length throughout. The successive crimps in each strip, however, would be formed of increasing depth from one end to the other of each strip so as to permit of the radial arrangement-of the bars when placed between strips as shown in Fig. 1. This crimping would be done by using successive dies of proper profiles, and a number of such dies of different depths could be assembled side by side in one press for successive use, as described in the co-pending application of Paul L. Price, Ser. No. 390,671, filed Sept. 6, 1929.

To reduce the number of dies so required I prefer, however, to form the crimps insuccessive groups, the-crimp in each group being of uniform depth, but those in any one group being slight- 1y deeper than those in the next preceding group by a uniform'amount and then, in the step of asserr'iblin'g the bars and strips, I-slightly distort one or more of the crirnps in each group sufficiently to produce the ultimate even progression in depth from one crimp to the next and so on for the entire length of the strip.

Cin'efrie'thod of proceeding along the abovedescribed lines is illustrated in Figs. 2 to a. In Fig. 2 the bent strip is shown as divided into three groups of two crimps each, 6, l6 and 26, which groups increase in depth (or height) from right 1 to leftby a uniform small amount. The crimps in any one group, however, are of equal heights. To effect the necessary slight distortion of the normal crimp outlines to produce a substantially regular and uniform progression in height from I right to left for all the six crirnps the right hand one of each group must be slightly depressed and the left hand one slightly raised. 1f the crimps have a wave outline between adjacent points of attachment to the straig t bars on either side of the strip, as here shown, the latter will have a sufficient flexibility to permit the necessary slight distortion by same proper procedure, such as the following:

The riveting operation is most easily performed on a slotted riveting bench with the assistance of a plurality of riveting dogs 9, 9, which serve as anvils for each rivet which is to be upset by harnmer blows in the usual way. There is one series 1; of riveting operations for each group of a straight bar and bent crimp added in the process of building up a panel.

Fig. 2 shows a partly assembled panel supported in the slot in bench 8 by dogs 9, 9, passing across the slot under the uppermost bent strip 6a, rivets 742 having been placed in position in the holes in the crowns of all crirnps before the dogs are slid into position.

The dogs la are formed of progressive thicknessses from one end of the series to the other as best shown in the enlarged detail view, Fig. 5. Evidently the dogs under the right hand member of each group of crimps 6, 16 and 26 will have a loose fit and those under the left hand member a fairly tight it, or one will have a normal iit and the other tight or loose. The operators loosen the more tightly fitting dogs by striking down on their projecting ends :0, best shown in Fig. 4, or by striking the base ends of the crimps at points Both these operations tend to slightly raise the crown of the crimp from the plane of its base represented by the straight bar 50. beneath it, and said procedure is continued until all dogs have approximately the same degree of closeness of fit in their crimps, as determined by feeling them.

Fig. 3 shows the next group of one straight bar 5?) and one bent strip 6?) placed in position over 5a, with rivets 7a extending through their registering rivet holes. These rivets are then upset by hammer blows, thus adding another unit to the panel. After this is done, or while it is being done, any right hand crimp of a group. which on test or mere observation obviously will need subsequent fiatten'ingjmay be tapped on'i'ts crown Z, to produce the desired slight distortion partially or wholly.

The dogs are then taken out from under strip 6a and inserted under strip 61)., thus lowering the partly completed panel a distance equal to that between adjacent straight bar centerTlines, and bringing about again the relative arrangement of parts shown in Fig. '2, whereupon the series of operations above describedare repeated. The progressive increases in thickness of dogs 9 may vary according to the flexibility of the bent strips and the consequent degree of ease of the humoring or distorting operation above described in this particular form of the process. For one class of radial floor grating having a six foot radius on the inner edge and a twelve foot radius on the outer edge, I find that a :progressive increase in thickness of about 5 -2 of an inch from one dog to the next gives good results, but in other classes of grating other dimensions might be found preferable.

The result of either of the above described methods of asembly is a grating panelhaving its straight bars diverging from each other at a uniform angle of inclination, said angle being.

a function of the progressive increase in depth of crimps and the distances between rivet centers, which together produce the particular mesh of grating desired. Such grating is as strong as parallel bar grating of the same type and weight and presents a most pleasing appearance to the eye. The joints atall points of contact between bars and strips could be produced by welding, or bolting, or interlocking of parts, if preferred, instead of by riveting.

If the bent strips are not too stiff, the necessary slight deformation of the crimps may be pro duced in the ordinary riveting operation without any of the refinements of humor-1mg above described. In such'case the principaldistortion would be a slight flattening of the right hand crimp of each group under the hammer blows of the operation of upsetting the rivet in that crimp, the dog in that crimp having a loose fit, while the dog under the left hand crimp of each group would have a very close fit.

In all cases it is customary to leave a slight possible clearance between dogs andrivet heads before the riveting operation is begun, and the operator then slips the end of a thin wedge under the rivet head to take up this clearance just before the hammering of that rivet. After that rivet is upset the wedge is withdrawn and inserted under the next rivet.

Having described my invention, I claim:

' 1. A grating suitable for use for flooring. and the like purposes which comprises in combination a plurality of straight bars each diverging from its neighbor at a uniform angle thereto, and a plurality of bent strips each filling a space between two adjacent straight bars and being fastened thereto at all points of contact.

2. A structure such as defined in claim 1 in which all points of contact between said bars and strips are uniformly spaced apart; whereby a grating of uniformlength of'mesh is produced.

3. As a new article of manufacture, a panel of grating having substantially the exterior outline of asector of a circle and being composed of a plurality of straight bars arranged radially of such circle at uniform angles of divergence one from another, and bent strips located between said bars and fastened thereto at all points of contact with one another.

4. A structure such as defined in claim 3 in which the converging ends of said straight bars are located in the arc of a circle, substantially concentric with that in which the outwardly flaring ends of said bars are located whereby the said panel is given the shape .of a truncated sector of a circle.

LOUIS N. LUMB. 

